CONSUMPTION Herbivory, Predation and ParasitismReading AssignmentHerbivory, Parasitism and PredationHerbivoryPlant defenses against herbivoresCoevolution of prey & predatorOvergrazed PasturesWhy is the World green?Using defensive compounds to one’s own advantageMimicryParasitism and DiseaseMalaria as a parasiteHow do individuals defend themselvesQuasi-speciesMeta-analysisParasites may manipulate the hostFlukes in snail affect its behaviorPredationIncluding Camouflage MimicryInducible DefensesPredator ControlVocabularyx3 lecture #7 UIC BioS 101 Nyberg 1CONSUMPTION Herbivory, Predation and ParasitismOrganisms are a desirable resource for other organisms. In consumption one species increases in abundance (+) at the expense of another (-).x3 #7 UIC BioS 101 Nyberg 2Reading Assignment• The Reading for today’s lecture is Chapter 53, pages 1063-1068.• Review of the disease lecture x1 08 may be useful. • The concept of ‘quasi-species’ in disease is a new idea that is not in your text.x3 lecture #7 UIC BioS 101 Nyberg 3Herbivory, Parasitism and Predation• Animals eating plants, herbivory, is a process distinguished from animals eating animals, predation, because 1) there is less action eating something that does not move, 2) consumption of animals normally kills the prey, but herbivory rarely kills the plant (why world is green?).• Parasites are animals (or microbes) eating animals, but parasites are smaller than their host and do not normally kill the host.x3 #7 UIC BioS 101 Nyberg 4Herbivory• Either roots or shoots eaten, not both.• Animals consume plants as food, but plants clearly encourage the consumption of nectar (pollination) and fruits (to disperse seeds).• Plants have a variety of ways to defend themselves against being eaten including being hard to digest and toxin production.x3 #7 UIC BioS 101 Nyberg 5Plant defenses against herbivores• Prickles, spines and hairs.• Compounds that taste bad and/or are harmful.• Hard structures that make them difficult to consume (silica in grasses).• Much of most plants is below ground, and takes a lot of energy to get to.Coevolution of prey & predator• Prey has an advantage if it can evolve better defenses against principle predators.• The predator gains resources if it evolves ways of getting around the prey defenses.• These opposing advantages can lead to an evolutionary ‘arms race’.x3 #7 UIC BioS 101 Nyberg 6x3 #7 UIC BioS 101 Nyberg 7Overgrazed Pastures• Animals can destroy all the vegetation in a habitat, but only do so when confined to a small area, as in a feed lot.• A high number of grazers per acre reduces vegetation aboveground biomass, but vegetation survives underground and as seeds.• Cows per acre is adjusted by ranchers to maintain the future productivity of the land.x3 lecture #7 UIC BioS 101 Nyberg 8Why is the World green?• Top-down model: Herbivore abundance is limited by predators• Bottom-up models: herbivore abundance is limited (controlled) by plant properties– Poor nutrition model: animals can’t grow fast enough on hard-to-digest food– Plant defense model: plants aren’t all eaten because they protect themselves• Landscape model: Animals move to more favorable patch before present patch gone.x3 #7 UIC BioS 101 Nyberg 9Using defensive compounds to one’s own advantage• Milkweeds produce a poison that stops many herbivores from eating it.• Monarch butterfly caterpillars not only have overcome the negative effects of this poison, they store the poison in their own body and it protects the butterfly from birds.• Fig. 53.13 tells of tree compounds defensive against beaver but used by beetles.Mimicry• Yellow, black & white stripes provide a signal that signifies ‘dangerous’. This is known as Mullerian mimicry.• Some species that don’t actually taste bad or sting, copy the warning (Batesian mimicry) to deceive predators. x3 #7 UIC BioS 101 Nyberg 10x3 #7 UIC BioS 101 Nyberg 11Parasitism and Disease• Infectious diseases are caused by viruses or organisms.• The disease causing organism must be able to find a host (colonization) and then successfully overcome host defenses.• Infected and uninfected hosts form a metapopulation with colonization and local extinction.x3 #7 UIC BioS 101 Nyberg 12Malaria as a parasite• A protista, Plasmodium, that infects two hosts– Humans– Mosquitoes• Multiple morphological forms in both hosts• Multiple defenses are known in humans– Sickle cell allele of beta hemoglobin– HLA-B53 individuals with this allele display a protein on cell surface that causes other cells to kill that cell.x3 #7 UIC BioS 101 Nyberg 13The immune system is our major defense against disease organisms. The immune system has many components including antibodies and cytotoxic cells. Diseases have evolved ways to quickly change surface proteins (changing more rapidly than the defense can respond) or make proteins that are not efficiently detected.The most dangerous diseases of humans are often new diseases (mutations that allow animal diseases to infect humans).How do individuals defend themselvesx3 #7 UIC BioS 101 Nyberg 14Quasi-species• A new concept of viral diseases looks at the virus not as a genotype but rather as a population of genotypes. • Viruses have high mutation rates and use the variation generated by mutation to effectively colonize diverse tissues.x3 #7 UIC BioS 101 Nyberg 15Meta-analysis• Studies which make observations and measurements of the natural world are called primary research• Studies of models are called theoretical research• Studies of primary studies, looking for consistent patterns are known as ‘meta- analysis’x3 #7 UIC BioS 101 Nyberg 16Parasites may manipulate the host• Infected individuals may behave differently than uninfected ones. • If the altered behavior benefits the parasite, we say the parasite manipulated the host.• Flatworm presence results in snail behavior that increases risk snail will be eaten by hawk which is next host in a complex life cycle.Flukes in snail affect its behaviorx3 #7 UIC BioS 101 Nyberg 17x3 #7 UIC BioS 101 Nyberg 18Predation• Organisms are a rich source of material and food for other organisms.• Predators are fast and powerful with good senses of a wide environment, but they have low abundances.• Prey defend themselves in diverse ways.x3 #7 UIC BioS 101 Nyberg 19Including Camouflagex3 #7 UIC BioS 101